Higher alkyl containing acetoxysilanes



United States Patent Office 3,542,832 HIGHER ALKYL CONTAINING ACETOXYSILANES Charles A. Roth, Saginaw, Mich., assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. Filed Aug. 15, 1968, Ser. No. 752,780 Int. Cl. C07f 7/08, 7/18 US. Cl. 260-4482 7 Claims ABSTRACT OF THE DISCLOSURE Alkylacetoxysilanes wherein the alkyl group contains 12 to 45 carbon atoms are disclosed. The alkylacetoxysilanes include compounds of the formulae CH3 CeHs O o,,H2..+1)si-o (i CH3, (C H2 1)Si-(O 0 CH3) 2 and (Cn Zn-H) i(0 3 CH3):

wherein n is 12 to 45 inclusive. The alkylacetoxysilanes are useful as evaporation retardants. Examples of specific alkylacetoxysilanes are octadecyldimethylacetoxysilane, octadecylphenyldiacetoxysilane and octadecyltriacetoxysilane.

0 05115 O (CuHnrn) S iO ii CH (GuH2n+1)Si(0 001192 and wherein n is an integer of from 12 to 45 inclusive.

The alkylacetoxysilanes of this invention can best be prepared by reacting an u-olefin with a chlorosilane in the presence of a platinum catalyst such as chloroplatinic acid. The chlorosilanes needed to provide the alkylacetoxysilanes of the present invention are dimethylmonochlorosilane, monophenyldichlorosilane and trichlorosilane. An wolefin and dimethylmonochlorosilane react to provide a compound having a formula An u-olefin and monophenyldichlorosilane react to provide a compound having a formula n 2n+1) s s Siclz An wolefin and trichlorosilane react to provide a compound having a formula (C H )SiCl The resulting chlorosilanes are then reacted with sodium acetate to produce the corresponding alkylacetoxysilane of the present invention. Another method of preparing the compounds of this invention is reacting the appropriate chlorosilane with acetic anhydride.

Patented Nov. 24, 1970 The u-olefin can be any alkene which has a carboncarbon double bond at a terminal carbon atom and has 12 to 45 carbon atoms. The u-olefin can be either straight chained or branched and include, for example, a-dO- decene, a-tridecene, rx-tetradecene, a-pentadecene, a-hexadecene, a octadecene, a-nonadecene,

CH CH (CH CH (CH (CH CH CH =CH(CH CH I 2 2 a) 2) 10CH3 21CH3 2= 2)11 a) 2)3 3)2(' 2) 'l s CH =CH(CH CH and 19CH3.

The alkylacetoxysilanes having a formula (CnH2u+1)(CHa)2SlOi 3CH3 include, for example, n-dodecyldimethylacetoxysilane, n-tridecyldimethylacetoxysilane, n-tetradecyldimethylacetoxysilane, n-hexadecyldimethylacetoxysilane, n-octadecyldimethylacetoxysilane, n-eicosyldimethylacetoxysilane, n-tetracosyldimethylacetoxysilane, n-triacontyldirnethylacetoxysilane, n-tetracontyldimethylacetoxysilane,

CH CHQCHQ CH3 0 The alkylacetoxysilanes having a formula 0 II (CuHQn-H) (C5115) Si(0 0 CH3):

include, for example,

1% a (CHaCO)2Si(CH2)9CH(CH2)aCH3 O CaHs CH2CH2CH3 and The alkylacetoxysilanes having a formula include, for example, n-dodecyltriacetoxysilane, n-tridecyltriacetoxysilane, n-tetradecyltriacetoxysilane, n-hexadecyltriacetoxysilane, n-heptadecyltriacetoxysilane, n-octadecyltriacetoxysilane, n-eicosyltriacetoxysilane, n-heneicosyltriacetoxysilane, n-docosyltriacetoxysilane, n-hexacosyltriacetoxysilane, n-nonacosyltriacetoxysilane, n-dotriacontyltriacetoxysilane, n-pentatetracontyltriacetoxysilane,

3 (CH2) BCH(CH3) 2) 9 a)a and CH (CH CI-I (CH CH CH Si (OOCCH 3 The alkylacetoxysilanes of the present invention are particularly useful as evaporation retardants. The alkylacetoxysilanes are applied to the surface of an aqueous body which is exposed to a gaseous atmosphere. The amount of alkylacetoxysilane applied is determined by several factors, such as, temperature of the aqueous body, temperature of the atmosphere above the aqueous body and the movement of the atmosphere or the aqueous body. The amount of the alkylacetoxysilane is usually applied to provide at least a monomolecular layer on the aqueous surface. However, more or less can be used depending upon the desired results. If one desires to control the rate of evaporation, one can apply less of the alkylacetoxysilane to provide some specific rate of evaporation which can be used as a means of controlling the temperature of an aqueous body.

The aqueous body can be a swamp, a field covered with water, a pond, a lake, a reservoir, or in a tank, in a ditch, in a dish, in a closed container with a controlled atmosphere and the like.

The alkylacetoxysilanes can be applied to the aqueous body as is or in the form of an organic solution or by any other means suitable to disperse the compound over the aqueous surface.

The alkylacetoxysilanes of the present invention retard the evaporation of water. The most effect alkylacetoxysilanes useful as evaporation retardants are those having a formula (C H2n 1)(CH Si(OOOCH The following examples are illustrative only and should not be construed as limiting the invention which is properly delineated in the appended claims.

EXAMPLE 1 A liter flask was charged with 252 g. of octadecene-l and heated to 110 C. To the heated octadecene-l was added 110 g. of dimethylmonochlorosilane and 0.15 cc. of chloroplatinic acid. The reaction was exothermic and the temperature rose to 128 C. and was held there for one-half hour. The excess dimethylmonochlorosilane was removed by heating the mixture. The product showed no silicon bonded hydrogen atoms when an infrared spectrum was obtained. The product obtained was (CIBHS'I) a)2 A vapor phase chromatogram was run on the product and a small amount of octadecene-l was still unreacted. The product was then heated to 120 C. and 50 g. of dimethylmonochlorosilane and 0.10 cc. of chloroplatinic acid was added. The reaction mixture was refluxed. The excess dimethylmonochlorosilane which was 45 g. was removed.

A flask was charged with 104.1 g. of the octadecyldimethylchlorosilane prepared above and was heated to 60 C. 32.13 g. of acetic anhydride was then slowly added to the heated mixture. After the acetic anhydride was added and the mixture was heated at 60 C. for one-half hour. The reacted mixture was then stripped under reduced pressure (about 160 mm. of Hg) at C. to remove the acetyl chloride which formed. The product was obtained was ll (01.1111) torrmsuo c on.

EXAMPLE 2 A 250 ml. flask was charged with 150 cc. of acetic acid and 16.4 g. of sodium acetate. The mixture was stirred until the sodium acetate dissolved. At room temperature, 41.6 g. of (C H )(CH )Si C1 was added to the sodium acetate solution, resulting in a two phase system. The mixture was then stirred and a white solution resulted. The mixture was stirred for 6 hours. The resulting product was 0 (0181137) (CHa)zSiO i CH3 in a yield of 44.5 g.

EXAMPLE 3 A flask was charged with 242 g. of mixture of a-olefins. The a-olfin mixture contained u-olefins having from 15 to 20 carbon atoms per molecule and the average molecular weight of the mixture was 242. To the mixture of a-olefins, 159.3 g. of (C H )HSiCl was added, the mixture being under a nitrogen atmosphere. The resulting mixture was heated to C. and 0.1 ml. of chloroplatinic acid was added. The temperature of the reaction mixture was maintained betwen 120 C. and C. for one hour. The resulting mixture was then stripped to C. at about 1 mm. of Hg pressure to remove any unreacted materials. The product obtained was (C H )(C H )SiCl where p is 15 to 20 in a yield of 273.1 g.

In a 100 ml. flask, 8.6 g. of sodium acetate was dissolved in 55 cc. of acetic acid and then 24 g. of the (C H )(C H )SiCl prepared above was added. A white precipitate formed immediately. The mixture was stirred for 7 hours. A three phase system resulted. The top phase of the three phase system was the product phase. The bottom liquid phase was acetic acid and sodium acetate and the bottom solid phase was sodium chloride. The mixture was separated by filtering, decanting and the product phase was stripped to remove any impurities. The product was obtained in a yield of 10.7 g. and was [I n H) e s) C a):

where p was 15 to 20 inclusive. The melting point was 24 C.

EXAMPLE 4 A 500 m1. flask was charged with 266 g. of the aolefin mixture as described in Example 3 and was then heated to 125 C. To the heated a-olefin mixture, 100 ml. of trichlorosilane and 0.25 ml. of chloroplatinic acid were added. The mixture was maintained between 100 C. to 150 C. for one hour. The resulting product was stripped at less than 1 mm. of Hg up to a pot temperature of C. The resulting product was obtained in a yield of 297 g. and was (C H )SiCl where p was 15 to 20 inclusive.

In a 300 ml. flask, 25.8 g. of sodium acetate was added and then dissolved in 150 ml. of acetic acid. The solution was stirred and then 47.9 g. of the (C H SiCl prepared above was added. The resulting mixture was stirred for 3 hours and then the product 6 was separated as described in Example 3. The product was obtained in a yield of 20.8 g. and was H Olefin Product (GpH2pi-l)si(OOCH3)B (I) CH3 where p was 15 to 20 inclusive. The product had a F- wmm a aOKCHzhgCH; melting point @147" 0.

EXAMPLE 0 CH3 A solution of each of the alkylacetoxysilane products 2= (C 2)o a omiiosuonnnon, of Examples 2, 3 and 4 in diethylether was prepared. Ten g drops of each ether solution was placed on the surface of 100 g. of tap water in 250 ml. stainless steel cups. (703 The resulting assemblies were placed in a controlled wHzha Hs CHSCOSKCHZMBCH: atmosphere of 65% relative humidity and 68 F. The 1 g weight of the cup, water and ether solution was initially made and then observed at time intervals of 1 day, 2 days, 5 days and 7 days. A control cup was also placed 2)12 s a (CH2)44CHa in the controlled atmosphere. The control was prepared as above, but without the alkylacetoxysilane solution. The octadecyldimethylacetoxysilane of Example 2 was pre- Omens E CHiCH pared in a 4 weight percent ether solution and the FW m a CH3OOSiCH2CH( 2)1o a alkylacetoxysilanes of Examples 3 and 4 were prepared H8 in 10 weight percent ether solutions. A 4 weight percent CH O CH CH ether solution of octadecyldimethylsilanol was used in 3 1| I 3 a place of the octadecyldimethylacetoxysilane. This was CHFCH(CH2)7CH(CH2)6CH3. cusoosuompcmcnmom used as a comparison to show the unique properties of the CH3 alkylacetoxysilancs.

The results below are the weight percentages of water lost in a given period under the test conditions.

Percent Percent water loss aftersavings Compound 1 day 2 days 5 days 7 days eor t izl (1) Control 7.3 14.7 35.0 47.2

(2 claflmsio-ocHa 1.3 2.3 8.2 18.2 61.4

(llaHs 0 (3) C15z0H3l41Si(OCCH3)2 6.5 13.9 31.7 43.1 8.7

ll (4) C15-2oH 1- S1(OCCH3)2. 6.6 14.0 31.4 44.0 6.8

E (5) CraHarSiOH 7.1 16.5 37.4 50.1 -6.1

EXAMPLE 6 EXAMPLE 7 Whfll the following olefins are reacted with When the following olefins are reacted with (CH HSiCl (C H )I-ISiCl in the presence of chloroplatinic acid and then conr tacted with sodium acetate as described in Example 2, the products as shown in the following table are obtained.

7 EXAMPLE 8 When' the following olefins are reacted with HSiCl in the presence of chloroplatinic acid and then contacted with sodium acetate as described in Example 4, the products as shown in the following table are obtained. 5

4. The alkylacetoxysilane according to claim 1 wherein the formula is CoHs (CnHZnH) S l-(O C CH3) 2 Olefin Product That which is claimed is: 1. An alkylacetoxysilane having a formula selected from the group consisting of 3 CH3 CoH O (C HZnH) SiO-C CH3, (C HZM-l) Si-(O 0 (mm and and 3 0 (CBHZDH) Si(O( JCH3) 5. The alkylacetoxysilane according to claim 4 wherein n has a value of from 15 to 20 inclusive.

6. The alkylacetoxysilane according to claim 1 wherein the formula is onmun) Si(O(BCHa)3 7. The alkylacetoxysilane according to claim 6 wherea in n has a value of from 15 to 20 inclusive.

References Cited UNITED STATES PATENTS 2,405,988 8/1946 Barry.

TOBIAS E. LEVOW, Primary Examiner P. F. SHAVER, Assistant Examiner US. Cl. X.R. 260448 

